|Putting It All Together|
|Yet, even with a map outlining the likely habitat of the owls,
scientists will still not be able to tell if the owls are surviving or
not. One last step is required. "We have to combine the
remote-sensing data with the demographic owl data," said Bill
Ripple, a member of the of the owl-habitat modeling team at Oregon State
University. In basic terms, the information collected about the owls on
the ground has to be matched up with the satellite maps.
Ripple said knowing the sheer amount of owl habitat is not enough to
determine whether the owls will survive. Other factors such as the
fragmentation of the old forest, the geometry of the owl habitat, and
the type of old forest all contribute to the owl's ability to survive
|The trick is in discerning just how these features affect owl health
and reproductive success. "We will first bring together years of field
data collected by field crews monitoring owl offspring," said Ripple.
He and his team will comb through years of ground-based studies to see
what features of the landscape in an owl's hunting range cause the owls
to increase or decrease in number.
Once these patterns have been found, the Oregon State University team will try to integrate them with the owl-habitat map. For instance, if large fragmentation of the owls habitat causes a decline in the population, then the researchers can rule out the areas on the map that are highly fragmented. "We have just begun this five-year study," said Ripple. "For all we know we may be unsuccessful." If they are successful, only minimal ground surveys will be needed to see whether the model continues to work. Cost will drop and the area could be surveyed quickly.
Of course, this entire plan may be thwarted by natural selection before these models can be completed. The barred owl, a close relative of the spotted owl, has invaded the Pacific Northwest, said Forsman. This owl can out hunt the spotted owl and is generally more resilient. Worse than that, the barred owls can breed with the spotted owls. Together they create a hybrid owl that can reproduce. "With the barred owls out there, the data are getting really hard to interpret. The associations [between the many variables] are becoming really muddled," said Forsman. "In the end the spotted owl may get kicked out of the forest anyway."
Although the population of northern spotted owls has stabilized for now, long-term threats remain, not all of them due to human activity. (Photograph courtesy Jerry Mires)